Description
Chiasmocleis parkeri is in the family Microhylidae, which is made up of small, narrow-mouthed frogs. The males range in snout-vent length from 14.23 - 16.51 mm, while the females were between 15.29 - 17.07 mm. Its body is larger than its head and it has thin arms giving it an ovoid shape. The snout in the dorsal view is truncated, but in the lateral view it is sub-elliptic. The mouth projects over the jaw. The eardrums are only 57% of the diameter of its eye. Their hands have a round palmer tubercle and basal webbing between fingers II - IV. Finger I is hidden and the other fingers have a relative length of II < III > IV. Their fingers are rounded with disks. Subarticular tubercles are present on fingers II, III, and IV. The planters are smooth. They have four identifiable toes and one that is hidden with a relative toe length of II < III < IV > V. Although they have basal webbing between the fingers of the hand, they lack webbing on the toes. In general the skin is smooth, except for wrinkles in the middle of the back and a few dermal spines towards the posterior of their body (Almendariz Cabezas et al. 2017).

DIAGNOSIS:

Chiasmocleis parkeri has subarticular and palmar tubercles, but the other species in the genus have smooth palms. Furthermore, C. parkeri have three obvious fingers and four pedals that differentiate them from C. tridactyla. Chiasmocleis parkeri also has tiny, cream colored dots all over and a brick-brown color on its dorsum with a lighter grayish belly while other species have more bluish spots on their belly and bright white spots everywhere else on their dark brown body. Chiasmocleis parkeri are bigger than the C. carvalhoi. Their straight and sub-elliptic snout is also a distinguishing characteristic that separates them from the C. hudsoni. Lastly, their advertisement call distinguishes them in that it lacks pulses contrary to the rest of the genus. Their average note emission rate per second is lower than the C. bassleri, and C. parkeri’s average dominant frequency is twice that of C. bassleri (Almendariz Cabezas et al. 2017).

COLORATION:

In life, the dorsum ranges from brick-red to maroon and is covered with tiny whitish-yellow dots. There is light brown on the belly, throat, inner surface of the limbs, and hands and feet. The color gets lighter towards the extremities of the digits. The eye is golden yellow in color with a black pupil (Almendariz Cabezas et al. 2017).

In preservative, individuals have sepia colored backs with no spots. An orange-brown color is observed towards extremities with small dots, along with an amber-colored belly, a darker throat, spots throughout the underside, and beige/white-colored soles of feet (Almendariz Cabezas et al. 2017).

VARIATION:

There is not enough statistical evidence to prove that they exhibit sexual dimorphism, but there are some small differences that can be identified. The males are smaller, have a darker throat, and are not as uniform in color as the females (Almendariz Cabezas et al. 2017).

Distribution and Habitat

Country distribution from AmphibiaWeb's database: Ecuador

View distribution map in BerkeleyMapper.

Chiasmocleis parkeri can be found in the Zamora Chinchipe province of Ecuador along the eastern foothills of the Andes and the western side of the Cordillera del Cóndor. At the time of the species description they were the only species of the family Microhylid that lived in the tepuyes in Ecuador. The montane environment consists of mosses, roots, and phytotelmata and soil that gets saturated quickly, allowing rain to pool and help with the spawning and development of the larvae. They were found at an elevation from 1224 - 1630 m above sea level (Almendariz Cabezas et al. 2017).

Life History, Abundance, Activity, and Special Behaviors
Individuals were found during both day and night (Almendariz Cabezas et al. 2017).

Bicolored eggs were found within a female specimen (Almendariz Cabezas et al. 2017).

Males had cream-colored, ovoid testicles (Almendariz Cabezas et al. 2017).

Males do not congregate when engaging in mating behaviors, rather they sing alone, randomly throughout both day and night. Their calls range from 3.96 - 4.09 kHz and sound like a metallic knock; the song is frequency modulated and has 72 notes without pulses. Chiasmocleis parkeri has a unique song among its genus due to its pulseless vocals. This could possibly be caused by a lack of vocal openings and sacs in the species (Almendariz Cabezas et al. 2017).

They eat a specialized diet of ants including Labidus spininodis, species of the genus Neoponera, and species of the genus Pleidole (Almendariz Cabezas et al. 2017).

Trends and Threats
Approximately 70 - 90% of the Chiasmocleis genus found in Ecuador is considered threatened. Deforestation and unsustainable agriculture are among the greatest threats to amphibians in Ecuador. Other anthropogenic threats include human infrastructure and settlements (Ortega-Andrade et al. 2021).

Possible reasons for amphibian decline

General habitat alteration and loss
Habitat modification from deforestation, or logging related activities
Intensified agriculture or grazing
Urbanization
Disturbance or death from vehicular traffic
Prolonged drought
Floods
Mining
Subtle changes to necessary specialized habitat
Disease

Comments

PHYLOGENETIC RELATIONSHIPS:

Maximum Likelihood analyses of COI, 12S, and 16S mtDNA along with CMYC, BDNF, SIA1, and Tyrosinase nDNA sequences confirmed that Chiasmocleis parkeri is part of the Chiasmocleis genus and a member of the C. hudsoni species complex, which includes C. antenori, C. carvalhoi, C. magnova and C. tridactyla. Chiasmocleis parkeri is most closely related to C. antenori, however, C. antenori was rendered paraphyletic in the analyses (Almendariz Cabezas et al. 2017).

ETYMOLOGY:

The species epithet, “parkeri”, is in honor of Ted Parker III, an ornithologist who led the expedition to Cordillera del Condor in 1991. It was his last field work trip funded and organized by the Conservation International and national institutions before his death in 1993 (Almendariz Cabezas et al. 2017).

References

Almendáriz Cabezas, A. de L., Brito M., J., Batallas Revelo, D. A., Vaca-Guerrero, J., Ron, S. R. (2017). "Una especie nueva de rana del género Chiasmocleis (Microhylidae: Gastrophryninae) de la Cordillera del Cóndor, Ecuador." Papéis Avulsos de Zoologia. São Paulo 57(10), 119–136. [link]

Ortega-Andrade, H.M., Rodes Blanco, M., Cisneros-Heredia, D.F., Guerra Arévalo, N., López de Vargas-Machuca, K.G., Sánchez-Nivicela, J.C., Armijos-Ojeda, D., Andrade, J.F.C., Reyes-Puig, C., Riera, A.B.Q., Székely, P., Soto, O.R.R., Székely, D., Guayasamin, J.M., Pesántez, F.R.S., Amador, L., Betancourt, R., Ramírez-Jaramillo, S.M., Timbe-Borja, B., Laporta, M.G., Bernal, J.F.W., Cachimuel, L.A.O., Jácome, D.C., Posse, V., Valle-Piñuela, C., Jiménez, D.P., Reyes-Puig, J.P., Terán-Valdez, A., Coloma, L.A., Lara, M.B.P., Carvajal-Endara, S., Urgilés, M., Muñoz, M.H.Y. (2021) "Red List assessment of amphibian species of Ecuador: A multidimensional approach for their conservation." PLOS ONE 16(5), e0251027. [link]

Species Account Citation: AmphibiaWeb 2022 Chiasmocleis parkeri: Parker’s Litter Frog <https://amphibiaweb.org/species/8813> University of California, Berkeley, CA, USA. Accessed Dec 2, 2023.

Citation: AmphibiaWeb. 2023. <https://amphibiaweb.org> University of California, Berkeley, CA, USA. Accessed 2 Dec 2023.

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